Self-purging air filter and speed reducing drive therefor



Oct; 22, 1963 I M. J. DUER 3,107,987

SELF-PURGING AIR FILTER AND SPEED REDUCING DRIVE THEREFOR qOriginalFiled March 17, 1961 3 Sheets-Sheet l IN VEN TOR.

Wax 5' Mia er AYY'ORNEY Oct. 22, 1963 M. J. DUER 3,107,987

SELF-PURGING AIR FILTER AND SPEED REDUCING DRIVE THEREFOR Original FiledMarch 17, 1961 s Sheets-Sheet 2 IIYVE AYYORNEY Oct. 22, 1963 M. J. DUER0 9 R FILTER AND SPEED REDUCING DRIVE THEREFOR Original Filed March 17,1961 s Sheets-Sheet s United States Patent 3,107,987 SELF-PURGING AERFTLTER AND SPEED REDUCING DRIVE THEREFOR Morris 5. Duer, lndlanapolis,Ind, assignor to General Motors Corporation, Detroit, Mich, acorporation of Delaware Continuation of application Ser. No. 96,459,Mar. 17, 1961. This application Sept. 27, 1962, Ser. No. 229,256

19 Claims. (Ci. 55-22%) This invention relates to air cleaners and moreparticularly to a self-purging air cleaner unit having a filtercartridge assembly rotatably driven by the air intake suction of anassociated device such as an internal combustion engine. The instantapplication is a continuation of my copending United States patentapplication Serial No. 96,459, filed March 17, 1961, which is nowabancloned.

The invention particularly contemplates an improved self-cleaning airfilter of the type disclosed in my copending United States patentapplication Serial No. 779,781, filed December 11, 1958, and entitledSelf- Cleaning Air Filter, and provides improved structure and rotatablemounting of a backwash cleaned filter cartridge assembly, of a suctiondriven turbine and of a speed reducing drive therebetween. The severalfeatures of the instant invention cooperate to provide a more compactand relatively inexpensive self-purging air filter unit providingmaximum filter ng efliciency and filter cartridge life and facilitatingassembly and inline inspection and servicing of the several components.With regard to certain of its more specific aspects, the inventioncontemplates an improved filter cartridge assembly having a plurality ofbackwash cleaned glass filter filter mats which are removable forcleaning and service replacement and protected from small stone damage,abrasion and air erosion. The invention further contemplates arelatively simple and inexpensive multi-stage compound epicyclic gearspeed reducer capable of quietly accommodating substantial variations inthe instantaneous speed and torque imparted thereto by the engine intakedriven turbine with minimal wear and friction losses.

The foregoing and other objects, advantages and features of theinvention will be apparent from the following description of anillustrative embodiment thereof, having reference to the accompanyingdrawings, in which:

FIGURE 1 is an elevational view of a self-purging air filter unitincorponating a filter cartridge assembly and speed reducing turbinedrive constructed in accordance with the invention, with portionsthereof broken away and shown in transverse section;

FIGURE 2 is an enlarged fragmentary view corresponding to a portion ofFIGURE 1 showing certain details of the filter cartridge assembly;

FIGURE 3 is a fragmentary sectional view taken substantially in thedirection of the arrows and in the horizontal transverse plane indicatedat 3-3 in FIGURE 1;

FIGURE 4 is a fragmentary sectional view taken substantially in thedirection of the arrows and in the plane of the line indicated at 4-4 ofFIGURE 3;

FIGURE 5 is an enlarged fragmentary sectional view corresponding to aportion of FIGURE 1 and showing the speed reducing drive in greaterdetail; and

FIGURE 6 is a fragmentary sectional view of the 3,1fi7fi8? Patented Oct.22, 1963 ice erally by the reference numeral 1i and is adapted to bemounted in the air intake system of an internal combustion engine. Theair filter unit comprises a filter cartridge assembly '12 which isrotatably mounted within a housing 14 and driven by an air intaketurbine 16 through a multi-stage compound epicyclic gear speed reducer18. The filter cartridge assembly is thus driven at a relatively slowrotational speed past a filter purging nozzle member 20. The nozzlemember is pivotally mounted and connectable to a suitable vacuum sourcethrough a tube 22 supported by a flanged base member 24;

The filter housing 14 includes the flanged base member 24 and aremovable cover assembly 26. The cover assembly is fabricated from aplurality of sheet metal members and includes an inverted disk-shapedhood 28 which is supported by the outer periphery of a frustoconicalstone restricting intake screen 30. The inner periphery of the screen 30is sealingly secured at 32 to an upstanding flange 34opening centrallyof a member 36 definingthe upper end wall of the cover assembly. Thisend wall member is secured outwardly to the upper end of a cylindricalside wall defining member 38. The lower end of the side wall memberslidably embraces and is removably secured to a flange 48 extendingradially outwardly from an inner cylindrical portion 42 of the basemember 24. The upper casirng assembly 26 and base flange 4i) thuscooperate to define a filter mounting chamber 44 having a central inlet46 defined by the end wall flange 34, the hood 28 and the intake screen30. The cylindrical portion of the base member is provided with a secondradial flange 48 mountable on an engine air intake member, not shown,and defines an outlet throat 50 axially spaced from the chamber inlet4-6.

A plurality of vanes '52 extend radially inwardly of the cylindricalbase portion 42 to a frusto-conical support hub 54. This hub cooperateswith the several vanes and the inner wall of the base portion to definea plurality of nozzle passages 56 which increase the air intake flowvelocity through the turbine 16. The upper end of the support hub 54 isinternally threaded at 58 and threadably supports a stationary ring gearand bearing supporting member 60 immediately below an integral ring geardefining flange 62. A tubular bearing support portion 64 depends axiallyof the threaded mounting portion of the support member 62 and convergesinwardly to a counterbored recess 66. This counterbored recess slidablysupports a combined radial thrust ball bearing 68 carried by a reduceddiameter end portion 70 of a turbine driven shaft 72. The inner race ofthe bearing 68 is interposed between a radial thrust shoulder defined bythe reduced diameter shaft portion and a central hub 7 4 of the turbinemember 16 which is threadably mounted thereon The turbine member is of asimple axial flow type and includes the hub 74- which is connected by aradially extending spider 76' to a cylindrical shroud 78 coax-iallyaligned with the adjacent end of the stationary support member 54. Theshroud supports a plurality of equistones? angularly spaced radiallyextending turbine blades or vanes 80 having close running clearances 81with the outlet throat 50 of the base member. The several turbine bladesare inclined to the axis of turbine and shaft rotation so that normalintake induced rotation of the turbine member causes the mating threadsbetween the urbine hub and shaft end between the support hub and memberat 6% to be reactively tightened. Any reverse air flow through theturbine outlet throat '50, as from intake manifold backfire, shifts theturbine member upwardly carrying the turbine shroud intobrakingengagement with the adjacent end of the base support hub 54. Suchbraking of the turbine member prevents back rotation which wouldotherwise loosen the turbine member and bearing support members withrespect to their mounting threads on the shaft and support hub.

As shown in FIGURE 1 and in greater detail in the enlarged fragmentaryviews of FIGURES 5 and 6, the speed reducer 18 includes the ring gearflange 62 of the stationary support member 60. The outer and upper endsurfaces of this ring gear flange rotatably support a cylindrical journmflange 82 and a radially extending thrust shoulder 84 of an inverted oropposing cup-shaped driven ring gear member '86. The second ring gearmember is rotatably retained on the stationary ring gear flange 62 by aflexible thrust plate 88 which is suitably secured to the bottom face ofthe ring gear member 86 by three equi-angularly spaced screws or bolts89, as shown. The two ring gear members thus cooperate to define drivehousing chamber 90 therebetween.

A sun gear 92 is threadably secured to the upper end of the turbinedriven shaft 72 within. the drive chamber 9 and drivingly engages threeplanetary gears )4 which are rotatably mounted on three equi-an-gularlyspaced journal hubs 95 formed integrally with and projecting downwardlyfrom a first planetary carrier 98. The carrier 98 is centrallyperforated and journaled on a reduced diameter end portion 160 of theturbine driven shaft. The several planetary gears 4- reactively engageinternal teeth 192 on the stationary ring gear flange 62 and thus imparta first-stage speed reducing rotation to the planetary gears 94 andtheir mounting carrier 98. A second sun gear 194 is formed integrally ofand extends upwardly from the spider portion of the first-stageplanetary carrier 98 in coaxial alignment with the journal openingtherethrough. This second sun gear drivingly engages three second-stageplanetary gears 106 which are rotatably mounted on equi-zmgularly spacedjournal hubs W8 formed integrally with and projecting downwardly from asecond planetary carrier 110. The several second-stage planetary gears1G6 outwardly engage the internal teeth 1592 of the stationary ring gearand gear teeth 112 formed internally of the driven ring gear member 86.The number of teeth 112, on the driven ring gear exceeds the number onthe stationary ring gear by one, two or three dependent upon the degreeof speed reduction desired and the meshing accommodation permitted bythe mating gear tooth configurations. The reactive engagement of theplanetary gears led with the stationary ring gear imparts a second stageof gear reduction to the planetary gears 1% and a third differentialstage of speed reduction to the driven output ring gear. This thirdstage of gear reduction is of a ratio proportional to the number of gearteeth in the driven ring gear and the difierential in gear teeth betweenthe driven and stationary ring gear members.

The several gears and the planetary carriers of the speed reducing driveare preferably precision molded of nylon or of other suitable plasticmaterials. Such precision components may thus be provided at nominalcost and the wear resisting bearing chanacteristics of such componentspermit prolonged service-free operation without lubrication. Thecarriers 98 and 116 and the planetary gears 94 and liil are preferablyidentical for parts interchangeability. This provides the carrier 11%}with a sun gear boss 114 which rotatably engages the head 116 of a boltmember 118 non-rotatably mounted in the upper end wall 128 of the drivengear 36. The sun gear boss 114 thus serves to axially position theseveral drive components internally of the drive chamber To providesubstantially lash-free, free-rolling contact between the several gearmembers, the sun gears 92 and-1ll4 of the illustrative embodiment havenine gear teeth formed on a ten tooth blank. These sun gear teeth meshwith mating teeth of the several planetary gears which have thirty-twoteeth each. The planetary gear engaged teeth of the stationary ring gearare formed to provide seventytwo teeth on a seventy-four tooth blank.Those of the driven ring gear 36 are formed to provide seventy-fiveteeth on a corresponding seventy-four tooth blank. The several gearsthus cooperate to provide first and second stage reduction of 9:1 eachwith a final differential stage of reduction of 25: 1. The resultantspeed reduction is thus in the order of 20251 through the illustrativespeed reducing drive. An intake driven turbine speed of approximately8000 rpm. is thus reduced to a filter cartridge driving speed ofapproximately 2' rpm.

As shown in FIGURES l4, the filter cartridge assembly 12 comprises anouter first-stage filter assembly 122, and an inner second-stage filter124. The outer filter is of bellows configuration and adapted to bebackwashed or vacuumed cleaned by the nozzle 20. The two filter unitsare clamped between longitudinally spaced and parallel peripheralflanges 126 and 128 of two hat-shaped end members 130 and 132. The crownportions of these two end members are oppositely disposed so that theupper member 139 defines a bowl-shaped flow deflecting recess oppositethe cover defined inlet 46 and the lower member 1132 embraces theturbine and speed reducing drive mechanism. The adjacent end walls 134and 135 of the members 130 and 132 are centrally perforated and aresecured to the driven ring gear member 86 by a wing nut 138 which isthreaded on the gear carried bolt '118 into engagement with a resilientgrommet 139 carried by the end wall 134. The filter assembly 12 is thusresiliently and frictionally snubbed to the upper ring gear androtatably driven by the turbine and gear reducing drive. The bellowsdefining outer surfaces of the outer filter 122 thus slowly pass insealing bearing engagement between radially extending and longitudinallyaligned slotted fingers 14d of the vacuum cleaning nozzle member 29which is preferably molded of a suitable wear resisting plasticmaterial. The cartridge end member 132 is perforated at 142 to provideengine intake induced air flow passage therethrough between the end wall136 and a cylindrical lower portion 144 which is sealing journaled onthe upper turbine inlet end of the cylindrical base portion 42 by aresilient lip seal 146 and a Teflon bearing seal member 148.

As best seen in FIGURES l and 2, the outer filter assembly 122 comprisesa plurality of annular glass fiber mats which are compressivelyinterposed in assembly between an outer plurality of annular perforatedsheet metal shield members 152 and 154 and an inner plurality ofresilient and pervious annular pads 156 of triangular cross-section. Theinner annular pads 156 are molded of latex impregnated hair' to providethe desired resiliency necessary to properly compress the glass fiberfilter mats. The perforated shield members are of frustoconical andopposing frusto-conical veed cross-sections providing limited axialresiliency and cooperating to define the desired external bellowsconfiguration. The fiber glass mats 156 are thus resiliently clampedoutwardly of the pads 156 by the mating peripheries of the shield rings152 and 154 and are clamped inwardly between the adjacent ends of aplurality of perforated filter supporting cylinders or rings 158. Theseinner filter supporting rings are nested longitudinally bet-ween theperipheral flanges of the cartridge end members 139 and 132. Thiscompressive clamping or compacting of the glass fiber filter matsbetween the perforated outer shield members and the inner lateximpregnated hair pads protects these mats from destructive abrasion bythe nozzle member and prevents destructive air fiow erosion of therelatively fine, soft and brittle glass fibers. Such glass fiber matshave been found to provide substantially better filteringcharacteristics than previously obtained with the somewhat moreexpensive wool felt filter construction disclosed in the above-mentionedapplication Serial No. 779,781.

The inner filter unit 124 is constructed of a cylinder of longitudinallypleated dry filter paper lot). This pleated cylinder extendslongitudinally between two molded plastic end rings 162 and 164embedding the opposite ends thereof. Any fine dust, moisture or erodedfiber glass particles which may pass through the fiber glass mats andthe latex impregnated hair pads are thus retained by the inner pleatedpaper filter. The two stages of filtration provided by the outerbackwash cleaned filter and the inner dry paper filter thus insurecontinuous dust and moisture free air supply for thousands of engineoperating hours without inspection or service replacement, even underthe most adverse dust conditions, although the structure of the housing,cartridge and drive mechanism permits maximum accessibility for iniineinspection, cleaning and service replacement of the several components.

While the foregoing description has been limited to one illustrativeembodiment incorporating the aspects of the invention in a compactself-purging filter unit, it will be apparent to those skilled in theart that various modifications and changes might be made therefromwithout departing from the sp rit and scope of the invention, as definedin the following claims.

I claim:

1. A self-purging air filter comprising a housing including a basemember having an outlet connectable to a high capacity air inductionsystem, a cover member defining a filter mounting chamber with said basemember and having an inlet opening coaxially spaced of said outlet, aplurality of vanes supporting a cylindrical hub centrally of the filtermounting chamber and coaxially of the outlet, said hub, vanes and outletdefining a plurality of nozzles; filter driving means supported by saidhub including a first ring gear non-rotatably supported by the upper endof said hub having a cylindrical annular flange adjacent the supportedportion thereof and hollow bearing support portion defining centrally ofsaid hub, a second ring gear having a cylindrical flange rotatablysupported on the first ring gear flange, said flanges each havinginternal gear teeth fiorrned thereon providing a limited gear toothdifierential therebetween, a shaft rotatably mounted by said bearingsupport portion, an axial flow turbine carried by said shaft wi hin saidoutlet for rotation by the air flow induced through said nozzle, a sungear carried by said shaft and spacedly embraced by the ring gearflanges, and planetary gear means interengaging the sun and ring gearsto rotatably drive said second ring gear at a very slow speed relativeto the turbine; a filter cartridge carried by said second ring gear forrotation therewith, said cartridge including two circular end members,at least the lower of said end members being hatshaped and having acentral end wall adjacent the upper end member and a cylindricalperforated wall portion spacedly embracing said drive means androtatably and sealin ly mounted with respect to the outlet andcylindrical filter means interposed between said end members; and meanssecuring the adjacent central wall portions of said end members to saidsecond ring gear; and a nozzle member pivotally mounted within saidfilter mounting chamber and connectable to a suitable vacuum source,said nozzle member having longitudinal filter cleaning slotstherethrough engaging the outer surface of said cylindrical filtermeans.

2. In a self-purging air filter mechanism as set forth in claim 1, saidcylindrical filter means comprising a glass 6:3 fiber filter matrix andresilient perv-ions wall means compressively compacting said glass fiberfilter matrix therebetween, and said filter cleaning nozzle memberengaging the outer surface of said wall means.

3. In a self-purging air filter mechanism as set forth in claim 2, saidcylindrical filter means funther comprising an inner filter cylinder oflongitudinally pleated filter paper.

4. In a self-purging air filter mechanism as set forth in claim 1, saidplanetary gear means including a first plurality of planetary idlergears drivingly interengaging said sun gear with said first ring gear, afirst planetary gear carrier comprising a spider portion and a pluralityof equiangularly spaced spindles depending therefrom, said first carrierspindles rotatably supporting said first planetary gears and thrustablyengaging said first ring gear, a second sun gear projecting upwardly andcoaxially from said first carrier spider portion, a second plurality ofplanetary idler gears drivingly interengaging said second sun gear withboth ring gears, a second planetary gear carrier comprising a secondspider pos tion and a second plurality of equiangularly spaced spindlesdepending therefrom, said second carrier spindles rotatably supportingsaid second planetary gears and thrustably engaging said first carrierspider portion, and thrust bearing means intermediate said second spiderportion and the adjacent end wall of saidsecond ring gear member, andthrustable bearing engagement between said carrier and ring gear memberssupporting said filter cartridge and permitting gear tooth loadequalizing radial movement of said carrier member to providefreerolling, lash-free drivingcngagemerit between the severalsimultaneous gear meshes.

5. in a self-purging air filter mechanism as set forth in claim 4, saidgear members being precision formed of a plastic material providinglimited gear tooth flexibility and permitting prolonged lubrication-freeoperation with minimal wear.

6. In a self-purging air filter mechanism, a base member having anoutlet conneotable to a high capacity air induction system, a covermember mounted on the base member and defining a filter mounting chamberhaving an inlet opening coaxial-1y spaced of said outlet, a cylindricalhub supported centrally of the outlet and filter mounting chamber andcooperating with said outlet to define a flow [restricting nozzle, drivemeans including a first ring gear non-rotatably supported by the upperend of said hub, said first ring gear having a cylindrical ainnularflange adjacent the supported portion thereof and having a hollowbearing support portion depending centrally of said huh, a second ringgear having a cylindrical flange rotatably supported on the first ringgear flange, said flanges each having internal gear teeth formed thereonproviding a limited gear tooth ditterential therebetween, an axial flowturbine rotatably mounted by said bearing support portion adjacent saidnozzle for rotation by air flow induced therethrough, a sun gearspacedly embraced by the ring gear flanges and drivingly connected tosaid turbine, and gear means interengaging the sun and ring gears torotatably drive said second ring gear at a very slow speed relative tothat of the turbine; a filter cartridge mounted on said second ring gearfor rotation therewith, said cartridge including two circular hat-shapedend members having spaced parallel peripheral flanges, means forsecuring the adjacent central end Walls of said end members to saidsecond ring gear for rotation therewith, the lower of said end membersspacedly embracing said drive means and having a cylindrical wallportion rotatably and :sealingly mounted with respect to the outlet andbeing perforated intermediate its cylindrical and end Wall portions topermit air flow therethrough, and cylindrical filter means interposedbetween the peripheral flanges of said end members; and a nozzle memberpivotally mounted within sm'd filter mounting chamber and connectable toa suitable vacuum source, said nozzle member having a longitudinallyextending filter cleaning (1 opening sealingly engaging the outersurface of said filter cylinder.

7. In a self-purging air filter mechanism as set forth in claim 6, saidplanetary gear means including a first plurality of planetary idlergears drivingly interengaging said sun and first ring gears, a firstcarrier member comprising a circular spider portion, a plurality ofequiangularly spaced spindles depending integrally from said spiderportion and rotatably supporting said first planetary gears andthrustably engaging said first ring gear, and a second sun gear portionintegral with and coaxial of said spider portion and projecting upwardlytherefrom, said second sun gear portion being spacedly embraced by saidring gear flanges, a second plurality of equiangularly spaced planetaryidler gears interchangeable with said first planetary gears anddrivingly interengaging said second sun gear portion and both of saidring gear members, a second carrier member interchangeable with saidfirst carrier member and comprising a second circular spider portion, asecond plurality of equiangularly spaced spindles depending integrallyfrom said spider portion and rotatably supporting said second planetarygears and thrustably engaging the spinder portion of said first carriermember, and a third sun gear portion integral with and coaxial of saidspinder portion and protecting upwardly therefrom said third sun gearportion thrustably engaging the end wall of said second ring gearmember, the thrustable bearing engagement between said carrier membersand said second ring gear member rotatably supporting said filtercartridge and permitting gear tooth load equalizing radial movement toprovide free-rolling, lash-free driving engagement between the severalsimultaneous meshes of the several gear members and portions.

8. In a self-purging air filter mechanism as set forth in claim 7, saidplanetary gear members being precision formed of a plastic materialproviding limited gear tooth flexibility and permitting prolongedlubrication-free operation with minimal wear.

9. In a self-purging air filter mechanism as set forth in claim 6, saidcylindrical filter means being of external bellows configuration andcomprising a plurality of annular glass fiber filter mats, a pluralityof perforated cylinders longitudinally stacked between the peripheralflanges of said end members and clamping the inner peripheries of theseveral filter mats in pairs therebetween and singly with respect to theadjacent end members, a plurality of annular pads molded of resilientpervious material and of triangular cross section, each of said padsoutwardly embracing one of said perforated cylinders, and a plurality ofperforated metal rings of frusto-conical and veed cross sectionsoutwardly embracing said glass fiber mats and molded pads, saidperforated metal rings being nested and resiliently clamped between saidperipheral flanges and compressively compacting said glass fiber filtermats against said molded pads and resiliently clamping the paired outerperipheries of said mats therebetween, and said nozzle member having aplurality of hollow tapered fingers extending radially inwardly andengaging the outer bellows defining surface of said perforated metalrings, said tapered fingers having longitudinally aligned slotstherethrough defining said filter cleaning opening.

10. In a self-purging air filter mechanism as set forth in claim 8, saidcylindrical filter eans being of external bellows configuration andcomprising a plurality of annular glass fiber filter mats, a pluralityof perforated cylinders longitudinally stacked between the peripheralflanges of said end members and clamping the inner peripheries of theseveral filter mats in pairs therebetween and singly with respect to theadjacent end members, a plurality of annular pads molded of resilientpervious material and of triangular cross section, each of said padsoutwardly embracing one of said perforated cylinders, and a plurality ofperforated metal rings of frusto-conical and veed cross sectionsoutwardly embracing said glass fiber mats and molded pads, saidperforated metal rings 8 being nested and resiliently clamped betweensaid peripheral flanges and compressively compacting said glass fiberfilter mats against said molded pads and resiliently clamping the pairedouter peripheries of said mats therebetween, and said nozzle memberhaving a plurality of members together, one of said end members beingper forated centrally or" its peripheral flange and connectable to theair induction system, an inner filter element interposed between theperipheral flanges of said end members and comprising a cylinder oflongitudinally pleated filter paper and plastic end rings molded toembed the opposite ends or" said filter paper cylinder, and an outerfilter assembly of external bellows configuration engageable with thebackwash nozzle and comprising a plurality of annular glass fiber filtermats, a plurality of perforated cylinders longitudinally stacked betweenthe peripheral flanges of said end members and clamping the innerperipheries of the several filter fiber mats in pairs therebetween andsingly with respect to the adjacent end members, a plurality ofresilient annular pads molded of latex impregnated fiber and oftriangular cross section, each of said molded annular pads outwardlyembracing one of said perforated cylinders, and a plurality ofperforated metal rings of frusto-conical and veed cross sectionsoutwardly embracing said glass fiber mats and molded pads, saidperforated metal rings being nested and resiliently clamped between saidperipheral flanges and compressively compacting said glass fiber filtermats against said molded pads and resiliently clamping the paired outerperipheries of said mats therebetween.

12. An air filter cartridge assembly of external bellows configurationcomprising two spaced end members, one of said end members beingcentrally perforated and connectable to an air induction system, aplurality of perforated cylinders longitudinally stacked between saidendmembers, a plurality of annular glass fiber mats, said perforatedcylinders clamping the inner peripheries of the several glass fiberfilter mats in pairs therebetween and singly with respect to theadjacent end members, a.

plurality of resilient annular pads each outwardly embracing one of saidperforated cylinders and molded of a latex impregnated fiber to providean outwardly tapered triangular cross section, and a plurality ofperforated metal rings outwardly embracing said glass fiber filter matsand molded pads, said perforated metal rings being of frusto-conical andveed cross sections and compacting said glass fiber filter mats againstsaid molded pads and resiliently clamping the paired outer peripheriesof said mats together. 1

13. An air filter cartridge assembly as set forth in claim 12, andfurther including an inner filter element comprisring a cylinder oflongitudinally pleated filter paper interposed between said end membersand spacedly embraced by said perforated cylinder member.

14. An air filter cartridge assembly of external bellows configurationcomprising two end members, one of said members defining a centraloutlet connectable to an air induction system, a plurality of perforatedcylinders longitudinally stacked between said end members coaxially ofsaid outlet, a plurality of annular pads each outwardly cmbracing'one ofsaid perforated cylinders and molded of a pervious material to providean outwardly tapered triangular cross section, a plurality of annularfilter mats clamped in pairs at their inner peripheries between saidperforated cylinders and singly between the end members and the adjacentperforated cylinders, and a plurality of perforated rings outwardlyembracing and compressively compacting said mats against said moldedpads and resiliently clamping the paired outer peripheries of said matstogether.

15. A compound planetary gear speed reducing mechanism comprising areaction ring gear member, a second output ring gear member rotatablysupported with re spect to said reaction ring gear member, said ringgear members each having a slightly difierent number of internal gearteeth providing a limited gear tooth differential therebetween, a firstrotatably driven sun gear spacedly embraced by the internal gear teethof said reaction ring gear member, a first plurality of planetary idlergears drivingly interengaging said sun gear with said reaction ring gearmember, a first planetary gear carrier member comprising a spiderportion and a plurality of equi-angularly spaced journal from, saidfirst carrier spindles rotatably supporting said first planetary gearsand thrustably engaging said reaction ring gear member, a second sungear carried by and projecting upwardly and coaxially from said firstcarrier spider portion, a second plurality of planetary idler gearsdrivingly interengaging said second sun gear with both of said ring gearmembers, a second planetary carrier member comprising a second spiderportion and a second plurality of equi-angularly spaced journal spindlesdepending therefrom, said second spindles rotatably supporting saidsecond planetary gears and thrustably engaging the spider portion ofsaid first carrier member, and thrust bearing means intermediate saidsecond spider portion and said second ring gear member, the thrustablebearing engagement between said carrier and ring gear members permittinggear tooth load equalizing radial movement of said carrier member toprovide free-rolling, lash-free driving engagement between the severalsimultaneous gear meshes.

16. A compound planetary gear speed reducing mechanism comprising acylindrical support member, a first bearing support and ring gear membernon-rotatably carried by said support member, said first member having aring gear defining flange portion adjacent the support portion thereofand having a frusto-conical bearing support portion depending therefrom,a second cup-shaped ring gear member having a second ring gear definingflange portion rotatably and thrustably supported on the ring gearflange of said first member and cooperating therewith to define a drivehousing chamber therebetween, said ring gear fianges each having aslightly different plurality of internal gear teeth formed thereonproviding a limited gear tooth differential therebetween, a driven shaftrotatably mounted by said depending bearing support portion in coaxiallyspaced relation to said ring gear members and projecting at one endthereof into said drive housing chamber, a first sun gear member carriedby and secured on the chamber projecting end of the driven shaft andspacedly embraced by the internal teeth of said first ring gear flange,a first plurality of equi-angularly spaced planetary idler gearsdrivingly interengaging said first sun and first ring gear members, afirst planetary gear carrier member comprising a circular spiderportion, a plurality of equi-angularly spaced gear journalling spindlesdepending integrally from said spider portion and rotatably supportingsaid first planetary gears and a second sun gear portion integral withand projecting upwardly and coaxially from said spider portion, saidsecond sun gear portion being spacedly embraced by the internal teeth ofat least one of said ring gear flanges, a second plurality ofequi-angularly spaced planetary idler gears interchangeable with saidfirst planetary gears and drivingly interengaging said second sun gearportion and both of said ring gear members, a second planetary gearcarrier member interchangespindles depending thereable with said firstcarrier member and comprising a second .circular spider portion, asecond plurality of equiangularly spaced gear journaling spindlesdepending integrally from said spider portion, said second spindlesrotatably supporting said second planetary gears and thrustably engagingthe spider portion of said first carrier member and a third sun gearportion integral with and coaxial of said spider portion andprojectingupwardly therefrom, said third sun gear portion thrustably engaging theend wall of said second ring gear member, the thrustable bearingengagement between said carirer and ring gear members permitting geartooth load equalizing radial movement of said carrier members to providefreerolling, lash-free driving engagement between the severalsimultaneous meshes of the several gear members and portions.

17. In a compound planetary gear speed reducing mechanism as set forthin claim 16, said planetary gear members being precision formed of asuitable plastic material providing limited gear tooth flexibilitycooperating with the permitted gear tooth load equalizing movement ofsaid carrier members and planetary gears to resolve gear errorcomponents between the simultaneous gear meshes thereby transmittingonly negligible average resultant gear error between the driven shaftand said second ring gear member.

18. A compound planetary gear speed reducing mechanism comprising areaction member having a ring gear defining flange thereon, a secondcup-shaped ring gear member having a second ring gear defining flangerotatably and thrustably supported on the ring gear flange of said firstmember and cooperating therewith to define a drive housing chambertherebetween, said ring gear flanges each having a slightly differentnumber of internal gear teeth providing a limited gear toothdifferential therebetween, a first rotatably driven sun gear spacedlyembraced by the internal gear teeth of said reaction ring gear flange, afirst plurality of planetary idler gears drivingly interengaging saidsun gear with said reaction ring gear member, a first planetary gearcar-rier member comprising a first spider portion and a first pluralityof equiangularly spaced journal spindles depending therefrom, said firstspindles rotatably supporting said first planetary gears and thrustablyengaging said reaction ring gear member, a second sun gear carried byand projecting upwardly and coaxially from said first spider portion, asecond plurality of planetary idler gears drivingly interengaging saidsecond sun gear with both of said ring gear members, a second planetarygear carrier member comprising a second spider portion and a secondplurality of equi-angularly spaced journal spindles depending therefrom,said second spindles rotatably supporting said second planetary gearsand thrustably engaging the spider portion of said first carrier member,and thrust bearing means intermediate said second spider portion and theadjacent end wall of said second ring gear member, the thrustablebearing engagement between said carrier and ring gear members permittinggear tooth load equalizing radial movement of said carrier member toprovide freerolling, lash-free driving engagement between the severalsimultaneous gear meshes.

19. In a compound planetary gear speed reducing mechanism as set forthin claim 18, said gear members being precision formed of a materialproviding limited gear tooth flexibility, and the permitted gear toothload equalizing movement of said carrier members and planetary gears andthe limited gear tooth flexibility cooperating to resolve gear errorcomponents between the several simultaneous gear meshes therebytransmitting only negligible average gear error between the driven sungear and said second ring gear member.

(References on following page) Refenences Cited in the file of thispatent UNITED STATES PATENTS Goodloe Nov. 15, Halstead Feb. 27, HollyJan. 7, Malcom Sept. 20, Bowen Feb. 13, Hart June 28, Double Nov. 7,Sebok Fan. 15,

Norbom Sept. 27, 1955 Parker May 20, 1958 Lunde June 2, 1959 Gruner Mar.7, 1961 P ritchard et a1 Apr. 11, 1961 HuX-ster Oct. 9, 1962 FOREIGNPATENTS 8 Sweden Aug. 17, 1943 Italy July 1, 1950 France Dec. 14, 1959UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pa tent No, 8 107987 October 22, 1963 Morris J. Duer It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 4, line 51, for "sealing" read sealingly column 5 line 4'7, for"defining" read depending Signed and sealed this 8th day of September1964.

(SEAL) Allest:

ERNEST W. SWIDER EDWARD J BRENNER Attesting Officer Commissioner ofPatents

1. A SELF-PURGING AIR FILTER COMPRISING A HOUSING INCLUDING A BASEMEMBER HAVING AN OUTLET CONNECTABLE TO A HIGH CAPACITY AIR INDUCTIONSYSTEM, A COVER MEMBER DEFINING A FILTER MOUNTING CHAMBER WITH SAID BASEMEMBER AND HAVING AN INLET OPENING COAXIALLY SPACED OF SAID OUTLET, APLURALITY OF VANES SUPPORTING A CYLINDRICAL HUB CENTRALLY OF THE FILTERMOUNTING CHAMBER AND COAXIALLY OF THE OUTLET, SAID HUB, VANES AND OUTLETDEFINING A PLURALITY OF NOZZLES; FILTER DRIVING MEANS SUPPORTED BY SAIDHUB INCLUDING A FIRST RING GEAR NON-ROTATABLY SUPPORTED BY THE UPPER ENDOF SAID HUB HAVING A CYLINDRICAL ANNULAR FLANGE ADJACENT THE SUPPORTEDPORTION THEREOF KAND HOLLOW BEARING SUPPORT PORTION DEFINING CENTRALLYOF SAID HUB, A SECOND RING GEAR HAVING A CYLINDRICAL FLANGE ROTATABLYSUPPORTED ON THE FIRST RING GEAR FLANGE, SAID FLANGES EACH HAVINGINTERNAL GEAR TEETH FORMED THEREON PROVIDING A LIMITED GEAR TOOTHDIFFERENTIAL THEREBETWEEN, A SHAFT ROTATABLY MOUNTED BY SAID BEARINGSUPPORT PORTION, AN AXIAL FLOW TURBINE CARRIED BY SAID SHAFT WITHIN SAIDOUTLET FOR ROTATION BY THE AIR FLOW INDUCED THROUGH SAID NOZZLE, A SUNGEAR CARRIED BY SAID SHAFT AND SPACEDLY EMBRACED BY THE RING GEARFLANGES, AND PLANETARY GEAR MEANS INTERENGAGING THE SUN AND RING GEARSTO ROTATABLY DRIVE SAID SECOND RING GEAR AT A VERY SLOW SPEED RELATIVETO THE TURBINE; A FILTER CARTRIDGE CARRIED BY SWAID SECOND RING GEAR FORROTATION THEREWITH, SAID CARTRIDGE INCLUDING TWO CIRCULAR END MEMBERS,AT LEAST THE LOWER OF SAID END MEMBERS BEING HATSHAPED AND HAVING ACENTRAL END WALL ADJACENT THE UPPER END MEMBER AND A CYLINDRICALPERFORATED WALL PORTION SPACEDLY EMBRACING SAID DRIVE MEANS ANDROTATABLY AND SEALINGLY MOUNTED WITH RESPECT TO THE OUTLET ANDCYLINDRICAL FILTER MEANS INTERPOSED BETWEEN SAID END MEMBERS; AND MEANSSECURING THE ADJACENT CENTRAL WALL PORTIONS OF SAID END MEMBERS TO SAIDSECOND RING GEAR; AND A NOZZLE MEMBER PIVOTALLY MOUNTED WITHIN SAIDFILTER MOUNTING CHAMBER AND CONNECTABLE TO A SUITABLE VACUUM SOURCE,SAID NOZZLE MEMBER HAVING LONGITUDINAL FILTER CLEANING SLOTSTHERETHROUGH ENGAGING THE OUTER SURFACE OF SAID CYLINDRICAL FILTERMEANS.